DE102018211102A1 - Valve assembly and fluid flow control element - Google Patents

Abstract

The present invention relates to a valve arrangement. The present invention further relates to a fluid flow control element. Furthermore, the present invention relates to a turbomachine system comprising such a valve arrangement and / or fluid flow control element. Furthermore, the present invention relates to a method and a use relating to the valve arrangement and / or the fluid flow control element.

Description

The present invention relates to a valve arrangement. Furthermore, the present invention relates to a fluid flow control element comprising a valve arrangement according to the invention. Furthermore, the present invention relates to a turbomachine system comprising a valve arrangement and / or a fluid flow control element. Furthermore, the present invention relates to a method for providing or repairing a turbomachine system comprising a valve arrangement and / or fluid flow control element. The present invention further relates to the use of a valve arrangement or a fluid flow control element.

Turbomachinery systems are an important part of today's industry and are of particular importance, for example, in the generation of energy. Here, turbomachine systems of this type have undergone various further developments. Even very established systems such as steam turbine systems are constantly subject to further developments and new requirements. For example, new challenges such as balancing the fluctuating feed-in from renewable energy sources such as wind energy and solar energy or even stricter requirements with regard to occupational safety and increased cost pressure result in a constant need to optimize such systems more and more.

For example, there is a desire for an easily controllable and more maintenance-friendly control system for the fluid flow of the turbomachine systems. At the same time, however, security must at least be maintained, especially for employees. An improvement should preferably also be achieved here. This is of particular importance for systems such as steam turbine plants, in which a fluid flow under high pressure is used. At the same time, however, the system should be as reliable and low-maintenance as possible, and high manufacturing costs resulting in high spare parts costs and increased risk of production defects should also be minimized.

These objects are achieved by the devices, method, and use as described herein and as set out in claims. The dependent claims and further description contain advantageous refinements of the invention which provide further advantages which can also solve additional problems.

According to one aspect, the present invention relates to a valve arrangement for regulating a fluid flow, comprising a stationary element and a movable element, the stationary element having a cavity in which the movable element moves, the movable element being suitable translationally along a first axis within of the cavity of the stationary element, wherein the movable element comprises a piston element and a rod-shaped coupling element, the piston element having an outside parallel to the first axis, the valve arrangement being designed such that a flow of the fluid flow between the stationary element and the outside of the piston element is prevented, the piston element having a contact edge which is suitable for contacting a valve seat, the piston element having a rear side opposite the contact edge, the coupling element being on the rear side of the piston element is increasing.

According to a further aspect, the present invention relates to a fluid flow control element comprising a valve arrangement according to the invention, a fluid flow line and a fluid flow inlet opening comprising a valve seat within the fluid flow line, the valve seat being suitable to contact the contact edge of the valve arrangement.

According to a further aspect, the present invention relates to a turbomachine system comprising at least one valve arrangement according to the invention and / or a fluid flow control element according to the invention.

According to a further aspect, the present invention relates to a method for providing or repairing a turbomachine system, preferably a steam turbine system, the method comprising installing or repairing a valve arrangement according to the invention or a fluid flow control element according to the invention.

According to a further aspect, the present invention relates to the use of a valve arrangement according to the invention or a fluid flow control element according to the invention for regulating the fluid flow of a turbomachine system, preferably a steam turbine system. The term “regulation” in the sense of the present invention denotes the setting of a desired fluid flow and in particular the blocking of the fluid flow.

For a more complete understanding of the present invention, reference is made to the following detailed description and the figures described in connection with it. However, the figures are only to be understood as an illustration of the invention and only represent particularly preferred embodiments and not a limitation of the invention.

shows a schematic cross section of a fluid flow control element according to the invention as a side view.

shows a schematic cross section of the in shown fluid flow control element according to the invention as a 3D view.

shows a schematic cross section of a similar fluid flow control element with a common valve arrangement as a side view.

In one aspect, the present invention relates to the aforementioned valve arrangement.

These allow the control of a fluid flow, in particular of a turbomachine system such as a steam turbine system, using only very small actuating forces. Surprisingly, it has been shown that by means of the valve arrangement according to the invention, the required actuating force, even when controlling high pressures of the fluid flow, for example more than 100 bar, for example 150 bar, by more than 90% compared to known systems, such as using a known valve arrangement as in shown, can be reduced. This is attributed to the fact that, in contrast to existing valve arrangements, the pressure of the fluid flow cannot act on the rear of the piston element. The valve arrangement is preferably designed such that the piston element is at least partially inside the cavity of the stationary element even when the valve is closed. For the purposes of the present invention, “closed position” means that the contact edge is in contact with the valve seat. Embodiments with, for example, additionally separated chambers are also conceivable, but this typically only increases the apparatus requirements without any noticeable additional gain. The design while preventing a flow between the outside of the piston element and the stationary element prevents the fluid flow from flowing to the rear of the piston element in an otherwise uncontrolled manner and thus, in particular, only making it possible to open the valve using very large actuating forces. Surprisingly, even an apparently filigree structure such as the embodiment mentioned below, in which the piston element is designed in a pot shape that is open to the contact edge side, can provide not only reliable control, but also exceptional long-term stability.

This allows the use of drive elements with drastically reduced requirements even in highly stressed areas, for example in turbomachinery systems such as steam turbine systems. In particular, simple electromechanical drive elements can be used which offer precise control, simple replacement, significantly reduced operating costs, maintenance costs and acquisition costs, and increased operational reliability. Even the use of, for example, hydraulic or pneumatic drive elements, which are designed for these significantly lower actuating forces, still has clear advantages over the use of, for example, currently used high-pressure hydraulics.

At the same time, it was surprisingly found that the valve arrangement according to the invention has a significantly increased reliability with a reduced manufacturing effort compared to solutions such as double-seat valves which, for example, have problems with the provision of the required tightness and at the same time involve a very high manufacturing effort. This applies in particular to highly stressed applications such as in the supply areas of the fluid flow to the turbine unit in turbomachinery systems. Steam turbine systems, in which a high pressure must be safely regulated, should be mentioned here as an example.

Some embodiments of the present invention are described below by way of example, which offer further special advantages. The subjects of these embodiments can also be combined with one another as desired in order to provide particularly advantageous embodiments for special applications.

In further embodiments, it is preferred that the rear side has at least one passage, the at least one passage connecting the area behind the rear side and the opposite area within the contact edge. This allows a particularly simple pressure equalization on both sides. For example, since no pressure equalization with the space outside the fluid flow line is required, it is a closed system, which further increases operational safety.

In further embodiments, it is preferred that the piston element has a pot shape open on the contact edge side with a side wall, the piston element having a rear wall opposite the contact edge, the rear wall having at least one passage. This makes it possible to significantly reduce the weight of the piston element, and surprisingly the valve arrangement is still reliable enough for use even in highly stressed conditions Cases as in the steam lines of a steam turbine system, for example, between the steam generator and the steam turbine. Surprisingly, corresponding valve arrangements, in particular with regard to their wear over longer periods of use, were found to be typically superior.

In further embodiments, it is preferred that the piston diameter is at least 75% of the valve seat diameter, more preferably at least 85% of the valve seat diameter, even more preferably at least 90% of the valve seat diameter. In particular, compact fluid flow control elements can be realized with this.

In further embodiments, it is preferred that the piston diameter is at most 99.5%, more preferably at most 99%, of the valve seat diameter. Surprisingly, it typically turned out to be advantageous to widen the area of the contact edge, an improved contact between the contact edge and the valve seat being achieved.

In further embodiments, it is preferred that the contact edge is located on a thickening of the piston element, preferably a bead. In particular, it is preferred that the thickening extends at least partially away from the first axis. By providing such a thickening, it is possible, for example, to provide an attack surface for the fluid flow, which exerts an additional pressure in the closed position of the valve and which keeps the valve closed. This is advantageous, for example, if the coupling element breaks or if the position of the movable element fails during the replacement of the drive.

In further embodiments, it is preferred that the outside of the piston element has at least one seal, more preferably at least two seals, the seal preferably being selected from the group consisting of labyrinth seals such as see-through labyrinth seals, piston rings and brush seals, more preferably from the group consisting of Labyrinth seals such as see-through labyrinth seals and piston rings. In particular, it is typically preferred if the outside of the side wall and / or the inside of the cavity opposite the outside of the side wall, preferably the outside of the side wall, has at least one labyrinth seal and at least one piston ring. Labyrinth seals can be designed in different forms. For example, they can either protrude from the surface in question or be present in the form of cutouts in the surface in question. For applications of high pressures of the fluid flow, such as for example in steam turbine flow systems, it has typically proven to be advantageous to design the labyrinth seal in the form of milled surfaces.

Corresponding millings for labyrinth seals are typically produced in a particularly simple manner, essentially perpendicular to the corresponding surface. However, such a milling can of course also be angled. Corresponding millings preferably have an angle of 45 ° to 135 °, more preferably an angle of 55 ° to 125 °, even more preferably an angle of 80 ° to 100 °, based on the corresponding surface in which the millings are made ,

In particular, it is typically preferred if the outside of the side wall and / or the inside of the cavity opposite the outside of the side wall, preferably the outside of the side wall, has at least one labyrinth seal and at least one piston ring. Such a labyrinth seal is typically sufficient to keep the leakage below an acceptable limit value, for example in highly stressed applications such as in steam feed lines to the turbine in steam turbine systems. The combination with, for example, a piston ring for further reduction and protection not only makes it possible to further reduce the leakage, but also to further increase the reliability.

It is typically preferred that the piston element has a round shape. In particular, it is typically preferred that the cross section of the piston element perpendicular to the first axis is oval or circular, more preferably circular. Although other shapes such as rectangular, square or triangular, in particular with rounded edges, are also conceivable, such round shapes have proven to be particularly advantageous for the present case, since they are excellent to seal and easy to manufacture.

In further embodiments, it is preferred that a stuffing box packing is arranged between the coupling element and the stationary element. The gland packing provides a particularly reliable seal against, for example, steam escaping from the valve arrangement or atmospheric entry in the valve arrangement. Here, different rings and / or bushings are preferably combined in order to achieve a highly resilient and yet reliable seal. The rings and / or bushings particularly preferably consist of graphite and / or stainless steel at least partially, more preferably at least 50% based on their number, more preferably completely.

In further embodiments, it is preferred that the coupling element is at least partially, more preferably in the area of the stuffing box packing, coated with a hard material coating. Such a coating can be provided, for example, with detonation coating, laser cladding, nitriding, plasma spraying, low-temperature plasma coating, flame spraying or combinations thereof, more preferably detonation coating, laser cladding, nitriding, plasma spraying or combinations thereof, even more preferably detonation coating, laser cladding or combinations thereof. A particularly preferred coating method is detonation coating. Particularly robust coatings can be achieved in this way.

In further embodiments, it is preferred that the stationary element has an injection channel in the area of the stuffing box packing. Such an injection channel can be used, for example, to inject a sealing compound such as graphite paste and to carry out an emergency repair. This is a very advantageous additional safeguard to further increase the reliability and safety of the valve arrangement.

In further embodiments, it is preferred that the coupling element has a fastening element, the fastening element being suitable for being releasably or non-releasably, preferably releasably, for being fastened to an electromechanical drive. Examples of the fastening element can be selected from the group consisting of indentations, bulges, threads for fastening screw connections and cavities for fastening by means of cylinder pins. For example, the end of the coupling element can be designed as a hammer head, the electromechanical drive for transmitting the translatory movement being releasably connected to the hammer head end of the coupling element via a suitable counterpart.

Typically, it is preferred in many embodiments that the connection between the drive and the movable element is non-positive or positive, more preferably positive. A powerful connection also achieves very good results. In particular, however, the positive connection for typical applications has proven to be an advantageous type of connection in order to provide a high level of reliability, but the connection can also be released again quickly, for example to replace the drive.

In further embodiments, it is preferred that the rear or the rear wall has at least 2 passages, more preferably at least 3 passages, even more preferably at least 4 passages. It is typically preferred that the passages are arranged symmetrically on the rear side or the rear wall. The use of several passages has proven to be particularly advantageous, since this apparently results in a more uniform flow of the fluid through the piston element or the rear wall and the movement of the movable element can take place evenly even if the movement is to take place very quickly. This is particularly advantageous, for example, for applications such as use as a main valve or as a valve in the fluid flow line of a steam turbine system between the steam generator and the steam turbine.

In further embodiments, it is preferred that the contact edge is rounded and is suitable for providing line contact with the valve seat. A particularly reliable seal is typically achieved here if the fluid storm is to be stopped completely.

According to a further aspect, the present invention relates to a fluid flow control element comprising a valve arrangement according to the invention, a fluid flow line and a fluid flow inlet opening comprising a valve seat within the fluid flow line, the valve seat being suitable to contact the contact edge of the valve arrangement. Such a fluid flow control element is preferably used in a turbomachine system. In particular, it is preferred that the fluid flow controlled here is used by the turbomachine for energy generation. Surprisingly, the fluid flow control elements according to the invention are also suitable for the extremely high requirements of controlling the fluid flow used as an energy carrier in a turbomachine system. For example, the fluid flow control element according to the invention can be installed particularly advantageously in the fluid flow line upstream of the turbine of the turbomachine.

In further embodiments, it is preferred that the fluid flow line has a piston chamber in the region of the valve arrangement, the piston chamber having an indentation, the indentation extending in the direction of the movable element. It was observed here that such an irregular shape of the piston chamber surprisingly enables an even better controlled movement of the movable element.

It is typically preferred for the indentation to reduce the distance between the piston space and the outside of the piston element to less than 75%, more preferably less than 65%, even more preferably reduced to less than 55% of the average distance between the piston space and the outside of the movable element, based on the cross section perpendicular to the first axis through the middle of the part of the movable element that protrudes from the cavity of the stationary element in the closed position. Surprisingly, this results in a stabilization of the movable element, whereby its wear is markedly reduced.

In further embodiments, it is preferred that the indentation extends over at least 3%, more preferably at least 5%, even more preferably at least 7%, of the piston space, based on the cross section perpendicular to the first axis through the center of the part of the movable element, that protrudes from the cavity of the stationary element in the closed position. It has proven to be advantageous not to make the indentation too small, in particular for applications in the case of fluid flows at high pressure, such as steam flows in steam turbine systems. In particular, high reliability is achieved here.

In further embodiments, it is preferred that the indentation extends over at most 20%, more preferably at least 17%, even more preferably at least 15%, of the piston space, based on the cross section perpendicular to the first axis through the center of the part of the movable element, that protrudes from the cavity of the stationary element in the closed position. It was also found that an excessively large dimensioning of the indentation typically does not bring about any improvement. In individual cases, the positive effect achieved by the indentation can even be reduced as a result.

In further embodiments, it is preferred that the fluid flow control element comprises an electromechanical drive which is releasably or non-releasably, preferably releasably, connected to the coupling element of the movable element and wherein the electromechanical drive is suitable for moving the movable element along the first axis. In particular, the detachable connection with an easily exchangeable electromechanical drive surprisingly allows the drive to be replaced quickly and safely even during operation.

According to a further aspect, the present invention relates to a turbomachine system comprising at least one valve arrangement according to the invention and / or a fluid flow control element according to the invention.

In further embodiments, it is preferred that the turbomachine system is a steam turbine system. For example, the high vapor pressure typically used here results in particularly high actuating forces required for regulating a conventional valve, as a result of which such turbomachine systems particularly benefit from the valve arrangements and fluid flow control elements according to the invention.

In further embodiments, it is preferred that the valve arrangement and / or the fluid flow control element are arranged in the steam line between the steam generator and the steam turbine. Since the highest vapor pressures are typically present here, the advantages according to the invention prove to be particularly great.

In further embodiments, it is preferred that the valve arrangement and / or the fluid flow control element is part of the main shutoff. In particular, it is typically preferred that the valve arrangement and / or the fluid flow control element function as a quick-closing valve. Since lower forces have to be applied and high reliability is achieved at the same time, use at this point has proven to be particularly advantageous.

In further embodiments, it is preferred that the valve arrangement and / or the fluid flow control element is part of a removal control valve. For example, part of the fluid flow can be removed here, for example, to be used for heating a preheater in front of the steam generator. Part of the fluid flow can also be removed and used as process steam, for example.

According to a further aspect, the present invention relates to a method for providing or repairing a turbomachine system, preferably a steam turbine system, the method comprising installing or repairing a valve arrangement according to the invention or a fluid flow control element according to the invention.

In further embodiments, it is preferred that the method comprises the at least partial replacement of an existing fluid flow control element comprising a high-pressure hydraulic drive for providing a fluid flow control element according to the invention comprising a low-pressure hydraulic drive or an electromechanical drive. The term “high-pressure hydraulic drive” preferably refers to a drive with at least 60 bar, more preferably at least 80 bar, pressure. The term "low pressure drive" also refers to the present invention preferably also a drive with a pressure of at most 30 bar, more preferably at most 20 bar, even more preferably at most 10 bar. With such upgrade methods, particularly large improvements are achieved for typical applications.

In further embodiments, it is preferred that the method comprises the at least partial replacement of an existing fluid flow control element comprising a non-electromechanical drive with a fluid flow control element according to the invention comprising an electromechanical drive. As has already been described, the change of the drive system possible in accordance with the present invention in connection with the high reliability of the fluid flow control element offers a particularly advantageous combination for typical turbomachine systems such as steam turbine systems in particular.

According to a further aspect, the present invention relates to the use of a valve arrangement according to the invention or a fluid flow control element according to the invention for regulating the fluid flow of a turbomachine system, preferably a steam turbine system. In this context, regulation means in particular the setting of a desired vapor pressure and in particular the blocking of the fluid flow. Surprisingly, the valve arrangement according to the invention and the fluid flow control element according to the invention not only allow reliable closure of the fluid flow line, but also allow a precise reduction or enlargement of the fluid flow. Especially in combination with the electromechanical drive, this allows fast and precise control depending on the current requirements. Although a valve arrangement according to the invention or a fluid flow control element according to the invention can theoretically also be used for regulating a secondary fluid flow such as a hydraulic oil flow, it is particularly preferably used for regulating the fluid flow used for energy generation in a turbomachine. Here it turned out to be particularly advantageous.

shows a schematic cross section of a fluid flow control element according to the invention as a side view. The fluid flow control element comprises a valve arrangement 1 , a fluid flow line 18 and a fluid flow inlet 17 within the fluid flow line 18 , The fluid flow inlet 17 has a valve seat that is suitable for the contact edge 8th the valve assembly 1 to contact.

The fluid flow line 18 points in the area of the valve arrangement 1 a piston chamber 15 on. In this piston room 15 there is an indentation 16 , the indentation 16 , towards the moving element 3 extends.

The valve assembly 1 serves to control the fluid flow through the fluid flow line 18 flows. In the in In the case illustrated, the fluid flow is a steam flow which is directed from the steam generator of a steam turbine system to the steam turbine as an example of the turbomachine system.

The valve assembly 1 comprises a stationary element 2 and a movable element 3 , the stationary element 2 a cavity 4 has, in which the movable element can move translationally along a first axis.

The movable structure comprises a piston element 5 and a coupling element 6 , The piston element 5 according to the in The embodiment shown is characterized by a cylindrical shape, the cylinder being on the side of the contact edge 8th has an open pot shape. The side wall 7 of the piston element 5 is limited by the outside of the piston element 5 , which extends parallel to the first axis and represents the outer surface of the cylinder .. The valve assembly 1 is designed such that a flow of the fluid flow between the stationary element 2 and outside of the piston element 5 is prevented. As a result, the high-pressure fluid flow does not lead to the rear of the piston element 5 the valve is relieved and can be moved with lower actuating forces. To the flow of the fluid flow between the outside and the stationary element 2 The outside of the piston element has an even safer prevention 5 a labyrinth seal and a piston ring as seals 11 on. These seals 11 are naturally found in the area of the outside, which does not come out of the cavity even when closed 4 of the stationary element 2 is moved out, so that a reliable flow of the fluid flow between the outside and the stationary element 2 is prevented.

Also identifies the piston element 5 the contact edge 8th and the opposite back wall 9 , The contact edge 8th is rounded to achieve line contact with the valve seat and to reliably close it. The contact edge is also located 8th on a bulge of the piston element 5 , which provides additional protection for the valve in the closed position. The back wall 9 has 4 passages, which are symmetrical around the connection from the rear of the piston element 5 and coupling element 6 are arranged. This enables pressure equalization of the area within the cup-shaped piston element 5 and the cavity 4 between the back of the piston element 5 and the stationary element 2 ,

The coupling element 5 the valve assembly 1 is in the middle of the back wall 9 of the piston element 5 attached and also represents a cylindrical shape. Here is the coupling element 6 provided with a hard material coating and a stuffing box packing 12 surround. The stuffing box packing 12 includes rings and bushings made of graphite and stainless steel. The stationary element 2 points in the area of the stuffing box packing 12 an injection channel, which makes it possible to inject graphite paste. In an emergency, this allows temporary sealing until a repair can take place.

The coupling element 5 is detachable with an electromechanical drive 14 connected to the movable element 3 inside the stationary element 2 can translate from left to right and back. The connection here is form-fitting via an indentation 16 on the coupling element 6 and a corresponding counterpart on the electromechanical drive 14 ,

The fluid flow control element can be used in new turbomachine systems, but can also be integrated into an existing system, for example, as part of an upgrade. The simple maintenance, for example a simple exchange of the electromechanical drive 14 Permitted during operation, also makes repair work on new and existing systems particularly easy and also increases the overall safety of the systems. In the event of damage, there is no need to wait until the turbomachine system shuts down or even the next maintenance cycle, but the flexible replacement in the shortest possible time enables the repair of such damage without further delay. Low-pressure hydraulic drives, for example, can also be repaired at least in a simplified manner, since a central high-pressure hydraulic circuit is no longer required for operation. Rather, a separate low-pressure hydraulic system can be used, which no longer requires other components to be shut down, but can also be switched off and repaired separately.

As part of a corresponding upgrade, at least part of the fluid flow control element, in particular the existing valve arrangement and the existing drive, is simply replaced, an existing supply line for a high-pressure hydraulic system being able to be shut down. Subsequently, direct control can take place via existing or new control electronics and, in the event of damage, a repair can be carried out in the rest of the turbomachine system independently of any high-pressure hydraulic system that may still be present. The replacement of the existing drive with an electromechanical drive has proven to be particularly advantageous 14 , because here, for example, an oil-based hydraulic circuit can be completely dispensed with, which entails additional requirements, safety risks and a larger space requirement.

shows a schematic cross section of the in shown fluid flow control element according to the invention as a 3D view.

shows a schematic cross section of a similar fluid flow control element with a common valve arrangement 1' as a side view. Here, too, the fluid flow control element has an indentation 16 ' in the piston chamber 15 ' to provide comparable conditions to the fluid flow control element according to the invention. However, the usual valve arrangement differs 1' used that by means of a drive 14 ' the movable element based on high-pressure hydraulics 3 ' inside the stationary element 2 ' moved translationally along the first axis and pressed onto the valve seat. In particular for opening the fluid flow inlet opening 17 ' a large force is required, which makes the high-pressure hydraulics necessary.

Analogous to that in case illustrated, the fluid flow control element is part of the fluid flow line 18 ' , which in turn is part of a steam turbine system as an example of a turbomachine system. Here, the fluid flow control element is located in the area of the fluid flow line 18 ' between the steam generator and the steam turbine.

The present invention has been described in more detail for the purposes of illustration using exemplary embodiments. However, the invention is not intended to be limited to the specific embodiment of these exemplary embodiments. Rather, the scope of the invention is to be limited only by the appended claims.

Claims (15)

Valve arrangement (1, 1 ') for regulating a fluid flow, comprising a stationary element (2, 2') and a movable element (3, 3 '), the stationary element (2, 2') having a cavity (4) in which the movable element (3, 3 ') moves, the movable element (3, 3') being suitable for translational movement along a first axis within the cavity (4) of the stationary element, the movable element (3, 3 ') 3 ') comprises a piston element (5) and a rod-shaped coupling element (6), wherein the piston element (5) has an outside parallel to the first axis, the valve arrangement (1, 1 ') being designed in such a way that a flow of the fluid flow between the stationary element and the outside of the piston element (5) is prevented, the piston element (5 ) has a contact edge (8) which is suitable for contacting a valve seat, the piston element (5) having a rear side opposite the contact edge (8), the coupling element (6) being fastened to the rear side of the piston element (5). Valve arrangement (1, 1 ') according to Claim 1 , The back has at least one passage (10), the at least one passage (10) connecting the area behind the back and the opposite area within the contact edge (8). Valve arrangement (1, 1 ') according to one of the Claims 1 to 2 , wherein the piston element (5) has a pot shape open on the side of the contact edge (8), the piston element (5) having a rear wall (9) opposite the contact edge (8), the rear wall (9) having at least one passage (10 ) having. Valve arrangement (1, 1 ') according to one of the Claims 1 to 3 The outside of the side wall (7) of the piston element (5) has at least one seal (11), the seal (11) preferably being selected from the group consisting of labyrinth seals, piston rings and brush seals. Valve arrangement (1, 1 ') according to one of the Claims 1 to 4 , wherein the contact edge (8) is rounded and is suitable for providing line contact with the valve seat. Fluid flow control element comprising a valve arrangement (1, 1 ') according to one of the Claims 1 to 5 , A fluid flow line and a fluid flow inlet opening (17, 17 ') comprising a valve seat within the fluid flow line, the valve seat being suitable to contact the contact edge (8) of the valve arrangement (1, 1'). Fluid flow control element according to Claim 6 , The fluid flow line in the region of the valve arrangement (1, 1 ') has a piston chamber (15, 15'), the piston chamber (15, 15 ') having an indentation (16), the indentation (16) extending in the direction of the Movable element extends. Fluid flow control element according to one of the Claims 6 to 7 , wherein the fluid flow control element comprises an electromechanical drive (14, 14 ') which is detachably or non-releasably connected to the coupling element (6) of the movable element and wherein the electromechanical drive (14, 14') is suitable for the movable element (3, 3 ') to move along the first axis. Turbomachine system comprising at least one valve arrangement (1, 1 ') according to one of the Claims 1 to 5 and / or a fluid flow control element according to one of the Claims 6 to 7 , Turbomachine system according to Claim 9 , wherein the turbomachine system is a steam turbine system. Fluid machine system according to one of the Claims 9 to 10 , wherein the valve arrangement (1, 1 ') and / or the fluid flow control element is arranged in the steam line between the steam generator and the turbine. Method for providing or repairing a turbomachine system, preferably a steam turbine system, the method for installing or repairing a valve arrangement (1, 1 ') according to one of the Claims 1 to 5 or a fluid flow control element according to one of the Claims 6 to 7 includes. Procedure according to Claim 12 The method comprises the at least partial replacement of an existing fluid flow control element comprising a high pressure hydraulic drive (14, 14 ') for providing a fluid flow control element according to one of the Claims 6 to 7 comprising a low pressure hydraulic drive (14, 14 ') or an electromechanical drive (14, 14'). Method according to one of the Claims 12 to 13 , The method comprising the at least partial replacement of an existing fluid flow control element comprising a non-electromechanical drive for a fluid flow control element according to one of the Claims 6 to 7 comprising an electromechanical drive (14, 14 '). Use of a valve arrangement (1, 1 ') according to one of the Claims 1 to 5 or a fluid flow control element according to one of the Claims 6 to 7 for regulating the fluid flow of a turbomachine system, preferably a steam turbine system.

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